There are three known influenza genera: genus A, genus B and genus C. Influenza belongs to the family of viruses referred to as myxoviruses, and more specifically to orthomyxoviruses. This family also includes “Thogoto-like” viruses. The orthomyxoviruses infect vertebrates. Virions in this family have a genome containing 7 to 8 segments of linear, negative-sense, single stranded RNA. (See, FIG. 2). Genomes of the influenza viruses are from 12000 to 15000 nucleotides in length.
Influenza types A and B are distinguishable based on the surface antigens hemagglutinin (H), which binds to host cells, and neuraminidase (N), which cleaves budding viruses from infected cells. Influenza A may be further classified into subtypes H1 to H16 and N1 to N9 based on the virus-encoded hemagglutinin and neuraminidase proteins, respectively. The influenza B virus is not further classified into subtypes. The influenza virus genome mutates continuously, resulting in frequent appearance of new antigenic variants and causing seasonal epidemics.
The oligonucleotides and methods disclosed are useful for detection of influenza A and influenza B nucleic acid targets in a variety of amplification and hybridization reactions. The present invention provides a more rapid and sensitive means of specifically detecting influenza A and B compared to previously known techniques (immunological and culture-based methods). Furthermore, the nucleic acids of the present invention are useful in various nucleotide amplification techniques, as described in further detail herein.